The major issue addressed by this investigation is the extent to which significant developmental problems in young children at biologic and social risk can be prevented by providing supportive home visitor services to their parents. Home visitor services were provided to 35 low income parents of sick preterm infants and it was found that the intervention acted to increase mothers' involvement and level of responsive interactions with their infants during the first year in comparison to the control group of 35 similar families. In addition, mothers' attitudes were influenced so that they became more realistic and appropriate about their own lives and expectations of their infants. Differences in infants' play and cognitive development associated with intervention began to emerge at 13 months and became stronger by 20 months. The proposed followup study to age 4 will examine: 1) The longevity of effects noted immediately following intervention; 2) Latent effects which may emerge subsequently; and 3) The developmental trajectory resulting from the original intervention. The effectiveness of the early intervention will be assessed as to the children's acquisition of language positive sense of self, positive relationships to peers, and decreased behavior problems, a well as in mothers' satisfaction with themselves and their children, and their interactions with their children.